The present invention relates to the fields of cancer treatment, inflammatory disease, and peptide chemistry.
The amino acid sequence Leu-pro-pro-ser-arg (SEQ ID NO:1) is a known immunostimulant and is described in papers by W. Weigle and is the subject of a US Patent. Briefly, the sequence of the present invention has been examined in U.S. Pat. No. 4,683,221 and claims were made for the stimulation of lymphocyte proliferation in mammals. U.S. Pat. No. 4,683,221 is included herein by reference, and contains descriptions of the biological effects of the SEQ. ID. 1 with regards to B cells, B cell differentiation and macrophages in vivo and in vitro experiments. Nowhere in the Weigle patent is mention of angiogenesis inhibition nor the connection between lymphocyte activiation and the inhibition of human neoplasms nor inflammation inhibition. Based on the work described in the Weigle patent, one would anticipate that the strong immuno-stimulating effect of the peptide leu-pro-pro-ser-arg (SEQ ID NO:1) would lead to increased inflammatory response.
Also, the Weigle patent does not describe any production methods of the subject peptide as being available from sea cucumber epithelial or other tissue.
Angiogenesis is the generation of new blood vessels into a tissue or organ. Under normal physiological conditions, humans or animals only undergo angiogenesis in very specific restricted situations. For example, angiogenesis is normally observed in wound healing, fetal and embryonal development and formation of the corpus luteum, endometrium and placenta. The control of angiogenesis is a highly regulated system of angiogenic stimulators and inhibitors. The control of angiogenesis has been found to be altered in certain disease states and, in many cases, the pathological damage associated with the disease is related to the uncontrolled angiogenesis.
Both controlled and uncontrolled angiogenesis are thought to proceed in a similar manner. Endothelial cells and pericytes, surrounded by a basement membrane, form capillary blood vessels. Angiogenesis begins with the erosion of the basement membrane by enzymes released by endothelial cells and leukocytes. The endothelial cells, which line the lumen of blood vessels, then protrude through the basement membrane. Angiogenic stimulants induce the endothelial cells to migrate through the eroded basement membrane. The migrating cells form a xe2x80x9csproutxe2x80x9d off the parent blood vessel, where the endothelial cells undergo mitosis and proliferate. The endothelial sprouts merge with each other to form capillary loops, creating the new blood vessel. In the disease state, prevention of angiogenesis could avert the damage caused by the invasion of the new microvascular system. Persistent, unregulated angiogenesis occurs in a multiplicity of disease states, tumor metastasis and abnormal growth by endothelial cells and supports the pathological damage seen in these conditions. The diverse pathological states created due to unregulated angiogenesis have been grouped together as angiogenic dependent or angiogenic associated diseases. Therapies directed at control of the angiogenic processes could lead to the abrogation or mitigation of these diseases.
One example of a disease mediated by angiogenesis is ocular neovascular disease. This disease is characterized by invasion of new blood vessels into the structures of the eye such as the retina or cornea. It is the most common cause of blindness and is involved in approximately twenty eye diseases. In age-related macular degeneration, the associated visual problems are caused by an ingrowth of chorioidal capillaries through defects in Bruch""s membrane with proliferation of fibrovascular tissue beneath the retinal pigment epithelium. Angiogenic damage is also associated with diabetic retinopathy, retinopathy of prematurity, corneal graft rejection, neovascular glaucoma and retrolental fibroplasia. Other diseases associated with corneal neovascularization include, but are not limited to, epidemic keratoconjunctivitis, Vitamin A deficiency, contact lens overwear, atopic keratitis, superior limbic keratitis, pterygium keratitis sicca, sjogrens, acne rosacea, phylectenulosis, syphilis, Mycobacteria infections, lipid degeneration, chemical burns, bacterial ulcers, fungal ulcers, Herpes simplex infections, Herpes zoster infections, protozoan infections, Kaposi sarcoma, Mooren ulcer, Terrien""s marginal degeneration, mariginal keratolysis, rheumatoid arthritis, systemic lupus, polyarteritis, trauma, Wegeners sarcoidosis, Scleritis, Steven""s Johnson disease, periphigoid radial keratotomy, and corneal graph rejection.
Diseases associated with retinal/choroidal neovascularization include, but are not limited to, diabetic retinopathy, macular degeneration, sickle cell anemia, sarcoid, syphilis, pseudoxanthoma elasticum, Pagets disease, vein occlusion, artery occlusion, carotid obstructive disease, chronic uveitis/vitritis, mycobacterial infections, Lyme""s disease, systemic lupus erythematosis, retinopathy of prematurity, Eales disease, Bechets disease, infections causing a retinitis or choroiditis, presumed ocular histoplasmosis, Bests disease, myopia, optic pits, Stargarts disease, pars planitis, chronic retinal detachment, hyperviscosity syndromes, toxoplasmosis, trauma and post-laser complications. Other diseases include, but are not limited to, diseases associated with rubeosis (neovasculariation of the angle) and diseases caused by the abnormal proliferation of fibrovascular or fibrous tissue including all forms of proliferative vitreoretinopathy.
Another disease in which angiogenesis is believed to be involved is rheumatoid arthritis. The blood vessels in the synovial lining of the joints undergo angiogenesis. In addition to forming new vascular networks, the endothelial cells release factors and reactive oxygen species that lead to pannus growth and cartilage destruction. The factors involved in angiogenesis may actively contribute to, and help maintain, the chronically inflamed state of rheumatoid arthritis.
Factors associated with angiogenesis may also have a role in osteoarthritis. The activation of the chondrocytes by angiogenic-related factors contributes to the destruction of the joint. At a later stage, the angiogenic factors would promote new bone formation. Therapeutic intervention that prevents the bone destruction could halt the progress of the disease and provide relief for persons suffering with arthritis.
Chronic inflammation may also involve pathological angiogenesis. Such disease states as ulcerative colitis and Crohn""s disease show histological changes with the ingrowth of new blood vessels into the inflamed tissues. Bartonellosis, a bacterial infection found in South America, can result in a chronic stage that is characterized by proliferation of vascular endothelial cells. Another pathological role associated with angiogenesis is found in atherosclerosis. The plaques formed within the lumen of blood vessels have been shown to have angiogenic stimulatory activity.
One of the most frequent angiogenic diseases of childhood is the hemangioma. In most cases, the tumors are benign and regress without intervention. In more severe cases, the tumors progress to large cavernous and infiltrative forms and create clinical complications. Systemic forms of hemangiomas, the hemangiomatoses, have a high mortality rate. Therapy-resistant hemangiomas exist that cannot be treated with therapeutics currently in use.
Angiogenesis is also responsible for damage found in hereditary diseases such as Osler-Weber-Rendu disease, or hereditary hemorrhagic telangiectasia. This is an inherited disease characterized by multiple small angiomas, tumors of blood or lymph vessels. The angiomas are found in the skin and mucous membranes, often accompanied by epistaxis (nosebleeds) or gastrointestinal bleeding and sometimes with pulmonary or hepatic arteriovenous fistula.
Angiogenesis is prominent in solid tumor formation and metastasis. Angiogenic factors have been found associated with several solid tumors such as rhabdomyosarcomas, retinoblastoma, Ewing sarcoma, neuroblastoma, and osteosarcoma. A tumor cannot expand without a blood supply to provide nutrients and remove cellular wastes. Tumors in which angiogenesis is important include solid tumors, and benign tumors such as acoustic neuroma, neurofibroma, trachoma and pyogenic granulomas. Prevention of angiogenesis could halt the growth of these tumors and the resultant damage to the animal due to the presence of the tumor.
It should be noted that angiogenesis has been associated with blood-born tumors such as leukemias, any of various acute or chronic neoplastic diseases of the bone arrow in which unrestrained proliferation of white blond cells occurs, usually accompanied by anemia, irpaired blood clotting, and enlargement of the lymph nodes, liver, and spleen. It is believed that angiogenesis plays a role in the abnormalities in the bone marrow that give rise to leukemia-like tumors.
Angiogenesis is important in two stages of tumor metastasis. The first stage where angiogenesis stimulation is important is in the vascularization of the tumor which allows minor cells to enter the blood stream and to circulate throughout the body. After the tumor cells have left the primary site, and have settled into the secondary, metastasis site, angiogenesis must occur before the new tumor can grow and expand. Therefore, prevention of angiogenesis could lead to the prevention of metastasis of tumors and possibly contain the neoplastic growth at the primary site.
Knowledge of the role of angiogenesis in the maintenance and metastasis of tumors has led to a prognostic indicator for breast cancer. The amount of neovascularization found in the primary tumor was determined by counting the microvessel density in the area of the most intense neovascularization in invasive breast carcinoma. A high level of microvessel density was found to correlate with tumor recurrence. Control of angiogenesis by therapeutic means could possibly lead to cessation of the recurrence of the tumors.
Angiogenesis is also involved in normal physiological processes such as reproduction and wound healing. Angiogenesis is an important step in ovulation and also in implantation of the blastula after fertilization. Prevention of angiogenesis could be used to induce amenorrhea, to block ovulation or to prevent implantation by the blastula.
In wound healing, excessive repair or fibroplasia can be a detrimental side effect of surgical procedures and may be caused or exacerbated by angiogenesis. Adhesions are a frequent complication of surgery and lead to problems such as small bowel obstruction.
Several kinds of compounds have been used to prevent angiogenesis. Taylor et al. have used protamine to inhibit angiogenesis, see Taylor et al., Nature 297:307 (1982). The toxicity of protamine limits its practical use as a therapeutic. Folkman et al. have disclosed the use of heparin and steroids to control angiogenesis. See Folkman et al., Science 221:719 (1983) and U.S. Pat. Nos. 5,001,116 and 4,994,443. Steroids, such as tetrahydrocortisol, which lack gluco and mineral corticoid activity, have been found to be angiogenic inhibitors.
Other factors found endogenously in animals, such as a 4 kDa glycoprotein from bovine vitreous humor and a cartilage derived factor, have been used to inhibit angiogenesis. Cellular factors such as interferon inhibit angiogenesis. For example, interferon .alpha. or human interferon .beta. has been shown to inhibit tumor-induced angiogenesis in mouse dermis stimulated by human neoplastic cells. Interferon .beta. is also a potent inhibitor of angiogenesis induced by allogeneic spleen cells. See Sidky et al., Cancer Research 47:5155-5161 (1987). Human recombinant .alpha. interferon (alpha/A) was reported to be successfully used in the treatment of pulmonary hemangiomatosis, an angiogenesis-induced disease. See White et al., New England J. Med. 320:1197-1200 (1989).
Other agents which have been used to inhibit angiogenesis include ascorbic acid ethers and related compounds. See Japanese Kokai Tokkyo Koho No. 58-131978. Sulfated polysaccharide DS 4152 also shows angiogenic inhibition. See Japanese Kokai Tokkyo Koho No. 63-119500. A fungal product, fumagillin, is a potent angiostatic agent in vitro. The compound is toxic in vivo, but a synthetic derivative, AGM 12470, has been used in vivo to treat collagen II arthritis. Fumagillin and O-substituted fumagillin derivatives are disclosed in EPO Publication Nos. 0325199A2 and 0357061A1.
The above compounds are either topical or injectable therapeutics. Therefore, there are drawbacks to their use as a general angiogenic inhibitor and lack adequate potency. For example, in prevention of excessive wound healing, surgery on internal body organs involves incisions in various structures contained within the body cavities. These wounds are not accessible to local applications of angiogenic inhibitors. Local delivery systems also involve frequent dressings which are impracticable for internal wounds, and increase the risk of infection or damage to delicate granulation tissue for surface wounds.
Thus, a method and composition are needed that are capable of inhibiting angiogenesis and which are easily administered. A simple and efficacious method of treatment would be through the oral route. If an angiogenic inhibitor could be given by an oral route, the many kinds of diseases discussed above, and other angiogenic dependent pathologies, could be treated easily. The optimal dosage could be distributed in a form that the patient could self-administer.
Inflammation is a major contributor to many diseases and as such, methods and compositions of matter have been sought to mitigate the detrimental effects of inappropriate activation.
Dermal inflammation is partially mediated via the conversion of phospholipids to either endoperoxides and consequently prostaglandins via cyclooxygenase and 5-HETE""s, or consequently leukotrienes via lipoxygenase (Kraghball and Voorhees. 1985. Curr. Probl. Derm. 13:1-10). Inhibition of either or both of these pathways is the means by which non-steroidal anti-inflammatory agents prevent an inflammatory response. Anti-inflammatory steroids act by inhibiting the release of arachidonic acid which can then be converted via either pathway to mediators of inflammation (Blackwell et al. 1980 Nature 287:147-149). It has been proposed that cytokines also mediate the inflammatory process and a better, or at least, equivalent inhibition of the inflammatory response may be achieved by inhibiting either cytokine production or the inhibition of the interaction of cytokines with their receptors on the cell surface of the inflammatory cell infiltrate. There have been several peptides isolated from sea cucumber of various species (Bizenheide, R., Tamori, Motokawa, et al. xe2x80x9cPeptides Controlling Stiffness of Connective Tissue in Sea Cucumbers.xe2x80x9d Bio. Bull 194:253-259. June 1998), but none are reported to have the sequence of the peptides of the present invention, nor do any peptides that has as its activity, the ability to inhibit an inflammatory response in a mammal. As a potentiator of a mammalian immune system response by way of activating lymphocytes and B cells and the associated cascades of immune-system protection, the peptide of the present invention may exert its anti-inflammatory and anti-cancer effects by an up-regulation of the mammalian immune system that is then able to destroy cancer cells directly or competitively bind to Fc receptors, thus mitigating their biological effects.
The present invention relates to a peptide, defined by the generic formula A-A-A-B-C (SEQ ID NO:2), wherein A is a non-polar amino acid, B is a polar amino acid and C is a charged amino acid. A sub-group of these peptides can be described by the formula A-Pro-Pro-B-C (SEQ ID NO:3), wherein A, B,and C have the meanings defined above. A specific embodiment of the peptide comprises the sequence LEU-PRO-PRO-SER-ARG (SEQ. ID NO: 1), which and is a fragment of various immunogammaglobulins, and especially of IgG, and described in U.S. Pat. No. 4,683,221 by William Weigle, et al as a portion of the Fc region of IgG. This peptide was initially isolated from the epidermis of the sea cucumber Cucumaria frondosa, and has both anti-cancer and potent anti-inflammatory activities. In a preferred embodiment the peptide comprises at least one D-amino acid.